Heat Recovery System

Does anyone have a good graphic and/or PDF to explain how a water heater/air conditioner heat recovery system works? I’m looking for something to imbed in the report to educate the buyer.
Thanks in advance,
Reece

Sorry Reese not quite sure what you are looking for heat pump/air conditioner or an HRV

http://www.wec.ufl.edu/extension/gc/harmony/documents/EH277.pdf